"When designing visual content, it's sometimes tempting to just get it out the door, but it's important to remember the basics of good design."
The below infographic from visage.co proposes 10 best practices for designing effective visual communication with examples, that will help ensure your visual content is beautiful and effective.
Some key takeaway:
Typography: All fonts should be legible and appropriate for what you are communicating.
Use No more than five colors in a single design. You can use different shades of a single color to distinguish.
Avoid unnecessary design, including 3D charts, graphics ornamental illustration or extraneous elements.